به نام خدا

دكتر محمد اماميفوق تخصص ريه

عضو هيات علمي دانشگاهرييس بخش ريه الزهرا

Acute and Chronic

Cough

Acute cough exists for less than three weeks -

Acute cough

acute respiratory tract infection an acute exacerbation of underlying

chronic pulmonary disease pneumonia pulmonary embolism

ETIOLOGY

subacute (three to eight weeks) or chronic (more than eight weeks) .

Chronic cough

upper airway cough syndrome asthma

gastroesophageal reflux

ETIOLOGY

Bronchiectasis Angiotensin-converting enzyme inhibitors Nonasthmatic eosinophilic bronchitis Bronchogenic carcinoma Interstitial lung disease Occult pulmonary infection Occult heart failure Occult aspiration Tracheobronchial foreign body or mass (other than bronchogenic carcinoma) Occupational asthma Nasal polyps Disorders of the external auditory canals, pharynx, larynx, diaphragm, pleura pericardium, esophagus, stomach, or thyroid Psychogenic

The most common cause Symptoms of postnasal drip include

frequent nasal discharge, a sensation of liquid dripping into the back of the throat, and frequent throat clearing .

no definitive criteria for its diagnosis mucosal thickening is a relatively

nonspecific finding

Upper airway cough syndrome

Asthma is the second leading cause of persistent cough in adults

the most common cause in children Cough due to asthma is commonly

accompanied by episodic wheezing and dyspnea.

Asthma

Often nocturnal Cough variant asthma can progress to

include wheezing and dyspnea .

"cough variant asthma"

A diagnosis of asthma is suggested when the patient is atopic or has a family history of asthma.

Asthma-related cough may be seasonal may follow an upper respiratory tract

infection may worsen upon exposure to cold, dry air,

or certain fumes or fragrances. A cough accompanied by wheezing or

dyspnea, or one that occurs following initiation of beta-blocker therapy also suggests asthma.

the best way to confirm asthma as a cause of cough is to demonstrate improvement in the cough with appropriate therapy for asthma (eg, one week of inhaled beta-agonist therapy)

Patients with this disorder demonstrate atopic tendencies

with elevated sputum eosinophils and active airway inflammation

absence of airway hyperresponsiveness Airway eosinophils and basement membrane

thickening are present in both asthma and eosinophilic bronchitis, but mast cell infiltration is noted only in asthmatics, which may explain the differences in airway reactivity .

Nonasthmatic eosinophilic bronchitis

The natural history of nonasthmatic eosinophilic bronchitis is variable.

13 percent developed asthma . Patients with recurrent episodes of

symptomatic eosinophilic bronchitis appear to be at increased risk of asthma and chronic airway obstruction .

second or third most common cause of persistent cough .

Many patients complain of symptoms of gastroesophageal reflux .

these symptoms are absent in more than 40 percent of patients .

Gastroesophageal reflux 

Stimulation of receptors in the upper respiratory tract (eg, in the larynx).

Aspiration of gastric contents, leading to stimulation of receptors in the lower respiratory tract.

An esophageal-tracheobronchial cough reflex induced by reflux of acid into the distal esophagus.

Prolonged (24 hour) esophageal pH monitoring, ideally performed with event markers to allow correlation of cough with esophageal pH, is generally considered the optimal diagnostic study, with a sensitivity exceeding 90 percent .

No specific pattern of the coughLong standingMay be productive

Most patients are relatively unaware of LPR with only 35 percent reporting heartburn.

Typical LPR symptoms include dysphonia/hoarseness, chronic cough, mild dysphagia and nonproductive throat clearing.

Laryngopharyngeal reflux

Mycoplasma pneumoniae Chlamydophila pneumoniae Bordetella pertussis

Respiratory tract infection

Chronic bronchitis should be considered in a patient who produces sputum on most days over at least 3 consecutive months, particularly during the winter months, over at least 2 consecutive years. In a smoker, the presence of chronic bronchitis may be predictive of progressive irreversible airflow obstruction.

Chronic bronchitis

o Cough is a major symptom of bronchiectasis

Bronchiectasis

nonproductive cough occurring in up to 15 percent of patients

treated with these agents It may appear within a few hours of taking

the drug, but may also become apparent only after weeks or even months.

The cough disappears within days or weeks following withdrawal of drug.

It is a more common complication in women than in men.

It does not occur more frequently in asthmatics than in non-asthmatics.

ACE inhibitors

Although the pathogenesis of the cough is not known with certainty, it has commonly been hypothesized that accumulation of bradykinin, which is normally degraded in part by ACE, may stimulate afferent C-fibers in the airway .

lung cancer is the etiology in less than 2 percent of the cases of chronic cough

neoplasms originating in the large central airways, where cough receptors are common.

Lung cancer

A new cough or a recent change in chronic "smoker's cough"

A cough that persists more than one month following smoking cessation

Hemoptysis that does not occur in the setting of an airway infection.

arteriovenous malformations retrotracheal masses tracheobronchomalacia Tracheal diverticuli Irritation of the external auditory canal by

impacted foreign bodies or cerumen habit or psychogenic

Rare causes

DIAGNOSTIC APPROACH

In the management of a patient with cough, the first step is to identify the cause of the cough and then treat the cause.

Treatment of subacute and chronic cough in adults

cough is very severe if treatment of the cause does not

lead to sufficient cough suppression or if treatment of the cause is not

possible or successful.

symptomatic,” “nonspecific,” or “indirect” antitussives

Opiates including morphine, diamorphine, and codeine are the most effective antitussive agents

Morphine and diamorphine are reserved for the control of cough and pain of terminal bronchial cancer patients, but codeine, dihydrocodeine, and pholcodeine can be tried in other cases of chronic cough.

methylether of morphine centrally acting antitussive Codeine is probably the most

commonly prescribed antitussive It should be used cautiously in patients

with reduced hepatic function, but it can be used without dose modification in patients with renal failure.

Codeine

Dextromethorphan is probably the most common non-opioid agent used for cough.

a synthetic derivative of morphine with no analgesic or sedative properties.

It is as effective as codeine in suppressing acute and chronic cough when given orally.

Side effects are few at the usual dose, but at higher doses, dizziness, nausea, vomiting, and headaches may occur.

It should be avoided in patients with hepatic insufficiency as it undergoes metabolic degradation in the liver.

Dextromethorphan

The American Academy of Pediatrics has highlighted the potential adverse effects and overdosage associated with antitussive preparations containing dextromethorphan in children,where dextromethorphan has been shown to be ineffective in cough due to upper respiratory tract infections.

Dextromethorphan should be used with caution also in patients on monoamine oxidase inhibitors as cases of central nervous depression and death have occurred.

a peripherally acting antitussive agent that presumably acts by anesthetizing stretch receptors in the lungs and pleura.

possible central effect.

 Benzonatate

Blocking the efferent limb of the cough reflex

Decreasing stimulation of cough receptors by alteration of mucociliary factors.

Ipratropium bromide

intranasal glucocorticoids are the most effective therapy for symptoms of allergic rhinitis .

oral and nasal antihistamines oral decongestants oral leukotriene receptor antagonists

Upper airway cough syndrome

First generation antihistamines are preferred over second generation ones (eg, cetirizine, fexofenadine, loratadine) due to the stronger anticholinergic effect, but concern over the sedating effects may limit their use .

Lack of improvement in cough after one to two weeks of empiric therapy for UACS is evidence that UACS is not the cause of the cough.

inhaled glucocorticoids (GC) inhaled bronchodilators The leukotriene receptor antagonists (LTRA) a short (one to two week) course of oral

prednisone

Cough variant asthma 

inhaled glucocorticoid oral glucocorticoids are needed for

refractory symptoms

Nonasthmatic eosinophilic bronchitis

lifestyle modifications acid suppression medication

Gastroesophageal reflux 

Acid suppression medications are a key component to the treatment of cough due to GERD . However, regimens proven effective in the management of GERD may not necessarily be the optimum regimen for cough due to GERD.

A 3 months, treatment at the highest recommended dose of a proton pump inhibitor is usually advocated. Not all patients respond and, in some, the response is only partial. One of the reasons for this failure may be the effect of the nonacid refluxate.

theophylline inhaled sodium cromoglycate a thromboxane antagonist (picotamide) the treatment of choice is withdrawal of the

ACE inhibitor. The cough will typically resolve within one to four weeks after stopping the ACE inhibitor, but occasionally will last up to three months .

Angiotensin converting enzyme inhibitors

Cough may also be a sign of disease in or outside the airways and lungs and a useful indicator for both patient and physician for initiating diagnosis and treatment of disease processes.

Impairment or absence of coughing can be harmful or even fatal in disease

When cough itself is persistent and excessive, it can be harmful and deleterious and may need to be suppressed directly.

Key Points

The most sensitive sites for initiating cough are the larynx and the tracheobronchial tree.

In the management of a patient with cough, the first step is to identify the cause of the cough and then treat the cause.

Patients on ACE inhibitor therapy should discontinue such therapy, with replacement by other appropriate treatments.

Postnasal drip, asthma, and GER are the three most common conditions associated with a chronic cough, and a diagnostic approach to exclude these conditions first is sensible.